The real world isn’t flat. So, why is your treadmill? Welcome to the world of incline treadmills. Setting steep inclines is better for burning fat, and for realistically preparing for races and other athletic events. An incline treadmill allows you to mimic the real world gradients of your next marathon, or burn twice as many calories as running flat. Finding the right incline treadmill is easy when you remember to consider these five basic factors:

1. Make sure the frame is sturdy and safe.

Back in 1998, Hal Higdon, winner of four World Masters Championships, mentor for over 250,000 marathon completers, and longest contributing writer to Runner’s World offered this timeless advice: “The control panel shouldn’t jiggle.”

That advice is still true today. First things first, the treadmill needs to be sturdy, and the display needs to be readable. This means the treadmill should have appropriate front and side handlebars to give you something to grab onto when the going gets tough. Also, if you’ve ever run on a treadmill with a wiggling screen in front of your face, you probably know that it can make for a nauseating run.

2. Find one with a good belt and motor.

That means a full-sized tread belt – at least 22 inches wide and 50 inches long. A full-size treadmill allows a normal sized adult a full range of motion.

The treadmill should have a surface that’s not too soft, but also isn’t too hard. Determining what is comfortable for you will require running on different models, but it’s worth your time.

3. Consider the latest maximum incline treadmills.

A 10 percent max incline is good and quite available. A 15 percent is even better. But why not consider going all out with a 40 percent max incline? More incline means more calories burned. An average 200-pound user walking at 2 mph for 20 minutes burns 87 calories. An average user at a 10 percent incline burns 157 calories. But at a 40 percent incline, an average user weighing 200 pounds burns a whopping 381 calories in just 20 minutes. Get started on your 40 percent incline now.

4. Take a look at the other features.

Incline treadmills have the ability to recreate an uphill run, and some of them can even do downhill also. Some treadmills even have monitors that make it easy to create a simulated experience. From running uphill in a forest or a desert, the right scenery can give you all the motivation you need to reach your goals. Unique running programs are also essential. Also, consider if it will sync up with your other devices such as tablets or phones.

5. Don’t forget the Warranty.

Incline treadmills move a lot. Instead of just going round and round, they go up and down too. When treadmills move more, they wear more. Marathoners, athletes, and competitors should look for a longer warranty because they’ll put even more wear on the machine.

Finding the right incline treadmill can be easy. Just remember the five important factors, and don’t forget to read the reviews!